On 30 March the IGNS reported that a moderate-sized hydrothermal explosion occurred in the Alum Lakes area, Wairakei, knocking over trees and destroying vegetation near the crater. Water levels at several of the Alum Lakes had dropped several weeks before the explosion.

Weekly Reports - Index

On 30 March the IGNS reported that a moderate-sized hydrothermal explosion occurred in the Alum Lakes area, Wairakei, knocking over trees and destroying vegetation near the crater. Water levels at several of the Alum Lakes had dropped several weeks before the explosion.

The Global Volcanism Program has no Bulletin Reports available for Maroa.

Volcano Types

Caldera(s)
Lava dome(s)

Tectonic Setting

Subduction zoneContinental crust (> 25 km)

Rock Types

Major
Rhyolite

Minor
Basalt / Picro-Basalt
Andesite / Basaltic Andesite

Population

Within 5 kmWithin 10 kmWithin 30 kmWithin 100 km

117
532
27,958
475,588

Geological Summary

The 16 x 25 km Maroa caldera formed sometime after 230 thousand years ago (ka) in the NE corner of the 30 x 40 km Whakamaru caldera, which is the largest of the Taupo Volcanic Zone. The Whakamaru caldera partially overlaps with the Taupo caldera on the south and was formed during the eruption of the Whakamaru Group ignimbrites between about 340 and 330 ka. The Maroa caldera was subsequently filled by at least 70 rhyolitic lava domes or flows, mostly erupted along a SW-NE trend. Lesser amounts of basalt were also erupted. The latest dated magmatic eruption took place about 14 ka, when the rhyolitic Puketarata tuff ring and lava domes were formed (Brooker et al., 1993). The Orakeikorako, Ngatamariki, Rotokaua, and Wairakei hydrothermal areas are located within or adjacent to the Whakamaru caldera. Large hydrothermal eruptions have occurred at the Orakeikorako thermal area during the Holocene, the latest immediately prior to the 1800-year-old Taupo eruption.

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Cones

Feature Name

Feature Type

Elevation

Latitude

Longitude

Rolles Peak
Apuahoe

Stratovolcano

570 m

38° 40' 0" S

176° 15' 0" E

Craters

Feature Name

Feature Type

Elevation

Latitude

Longitude

Whakamaru

Pleistocene caldera

38° 30' 0" S

176° 5' 0" E

Domes

Feature Name

Feature Type

Elevation

Latitude

Longitude

Ben Lomond

Dome

740 m

38° 35' 0" S

175° 58' 0" E

Caws Road

Dome

598 m

38° 24' 0" S

175° 50' 0" E

Kaimanawa

Dome

534 m

38° 35' 0" S

176° 14' 0" E

Mangatoetoe

Dome

641 m

38° 30' 0" S

176° 7' 0" E

Mangatutu

Dome

525 m

38° 25' 0" S

176° 3' 0" E

Maraemanuka

Dome

610 m

38° 28' 0" S

175° 51' 0" E

Maroa North

Dome

770 m

38° 28' 0" S

176° 2' 0" E

Maroa South

Dome

686 m

38° 30' 0" S

176° 2' 0" E

Maroa West

Dome

792 m

38° 30' 0" S

176° 0' 0" E

Maroanui

Dome

897 m

38° 31' 0" S

176° 1' 0" E

Maungaiti

Dome

774 m

38° 20' 0" S

175° 56' 0" E

Mokai

Dome

740 m

38° 34' 0" S

175° 55' 0" E

Ngangiho

Dome

656 m

38° 35' 0" S

176° 3' 0" E

Ngautuku

Dome

626 m

38° 23' 0" S

176° 1' 0" E

Oheinui

Dome

805 m

38° 29' 0" S

176° 5' 0" E

Oruahinawe

Dome

526 m

38° 36' 0" S

176° 7' 0" E

Oruanui

Dome

720 m

38° 35' 0" S

176° 1' 0" E

Pohaturoa

Dome

520 m

38° 24' 0" S

176° 1' 0" E

Pokuru

Dome

673 m

38° 29' 0" S

175° 51' 0" E

Pukeahua

Dome

715 m

38° 26' 0" S

176° 0' 0" E

Pukemoremore

Dome

686 m

38° 31' 0" S

175° 58' 0" E

Puketarata

Dome

690 m

38° 33' 0" S

176° 3' 0" E

Rapanui

Dome

740 m

38° 22' 0" S

175° 54' 0" E

Te Terata

Dome

704 m

38° 32' 0" S

175° 53' 0" E

Tirohanga

Dome

590 m

38° 27' 0" S

175° 53' 0" E

Tuahu

Dome

591 m

38° 28' 0" S

176° 4' 0" E

Tutukau

Dome

800 m

38° 28' 0" S

176° 7' 0" E

Upper Atiamuri

Dome

535 m

38° 19' 0" S

176° 6' 0" E

Whakapapataringa

Dome

680 m

38° 32' 0" S

176° 10' 0" E

Thermal

Feature Name

Feature Type

Elevation

Latitude

Longitude

Atiamuri

Thermal

Craters of the Moon
Karapiti

Thermal

38° 38' 0" S

176° 5' 0" E

Geyser Valley

Geyser

38° 38' 0" S

176° 5' 0" E

Ngatamariki

Thermal

310 m

38° 32' 0" S

176° 10' 30" E

Ongarato

Thermal

Orakeikorako

Thermal

360 m

38° 28' 30" S

176° 9' 0" E

Rotokaua
Rotokawa

Thermal

360 m

38° 37' 30" S

176° 12' 0" E

Waiora Valley

Thermal

38° 38' 0" S

176° 5' 0" E

Wairakei

Thermal

460 m

38° 37' 30" S

176° 4' 0" E

Photo Gallery

Ngahigo lava dome is one of at least 70 post-caldera lava domes erupted within the Maroa caldera, which formed sometime after about 230,000 years ago north of the Taupo caldera. The youngest of the post-caldera lava domes is Puketarata, which was emplaced within a rhyolitic tuff ring about 14,000 years ago. The domes were erupted along a general SW-NE trend, parallel to the structural trend of the Taupo volcanic zone. No Holocene eruptions have occurred, but vigorous thermal activity continues.

Photo by Ichio Moriya (Kanazawa University).

Spectacular siliceous sinter terraces at Orakeikorako cover an area of about 1 cu km, forming one of New Zealand's most impressive thermal areas. The thermal area lies along the Waikato River at an altitude of 260-360 m on the eastern side of the Maroa volcanic center. Hydrothermal explosions took place at five centers at Orakeikorako prior to the Taupo pumice eruption about 1800 years ago, depositing explosion breccias that immediately underlie the Taupo Pumice.

Photo by Richard Wysoczanski, 1994 (Smithsonian Institution).

Algae colors the surface of spectacular siliceous sinter terraces at the Orakeikorako thermal area. This geothermal area is one of the principal hydrothermal fields of the Taupo volcanic zone. It lies on the banks of the Waikato River where the Paeroa Fault divides into smaller branches that intersect the eastern margin of the Maroa volcanic center. Orakeikorako contains sinter sheets covering an area of about 1 cu km. Flooding of the river hydroelectric power generation has drowned about 70% of the hot springs.

Photo by Richard Wysoczanski, 1994 (Smithsonian Institution).

References

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title.

WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.

EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).